For many years, photographs were produced in an analog process based on silver-halide chemistry. An image was captured by exposing a photo-sensitive film to a scene by an optical system in a camera. The photo-sensitive material coated on the film include silver halide emulsions. The silver halide emulsions can capture photons and record a latent image corresponding to the captured image. The exposed photo-sensitive film was chemically developed to convert the latent image into a dye image on the film. A photo-sensitive paper was in turn exposed to the dye image on the film. A photographic print is finally obtained after the exposed paper is processed. As with other systems, photography can benefit from digital techniques applied to various aspects of the process. Image data, captured by a digital camera or digitized from a reflective print or a film by a scanner, can be transmitted anywhere in the world almost instantaneously and then stored on mass storage devices. Multiple copies can be easily made and stored at different locations. The image data can be manipulated using image-processing software.
As well known in the photographic industry, it is desirable for the photographic prints to have the look and feel of the conventional silver halide based photographic prints, even if the images are captured in a digital process. To fulfill this need, the digital images can be digitally exposed on a photographic paper and subsequently developed, bleach/fixed, and washed in the conventional photographic chemical processes. Such produced photographic prints have equal image quality and the same look and feel as the conventional photographs for viewing and sharing.
The process for generating photographic prints includes a number of different steps. Image data are often compressed in the digital cameras. To generate a print of such compressed images, one must uncompress the data and perform image processing on the uncompressed image data. The image processing operations can include tone or color adjustment, neutral balance, and image enhancement. Additional image design and text information may also be added to the digital image. Digital prints based on the digital images can be produced using a variety of digital printing technologies such as digital silver halide, ink jet, thermal dye sublimation, and electrophotography. In the example of the digital silver halide printing, the image data is converted into an image exposure pattern to expose a photosensitive material coated on a substrate to form a latent image. The latent image is converted to form a dye image when the photosensitive material is processed. Information may be printed on the back of the prints. The prints are cut and packaged before shipping. Any of these processes can become a bottleneck that limits the overall speed of the system.
Thus, there is a need for a method and apparatus that can efficiently reproduce photographic prints in response to input digital images.